Answer:
8.0 x 10⁻³
Explanation:
(8.0×10⁻³) - (2.5×10⁻⁵)
= (8.0×10⁻³) - (2.5 × 10⁻² x 10⁻³) (factor out 10⁻³)
= 10⁻³ [ 8 - (2.5 x 10⁻²) ]
= 10⁻³ [ 8 - 0.025 ]
= 10⁻³ [ 7.975 ]
= 7.975 x 10⁻³
however we can observe that both original numbers are expressed to 2 significant figures, hence we must express our answer also in 2 significant figures by rounding 7.975 to 8.0, thereby giving us:
8.0 x 10⁻³
